1. FIeld of the Invention
The present invention relates to a shift mechanism for a change-speed gearing in a power transmission, and more particularly to a pneumatically or hydraulically operated shift mechanism for a change-speed gearing in a power transmission which includes a pneumatic or hydraulic acuator, a shift rod axially slidably carried on a support structure and operatively connected to the actuator for reciprocating movement, and means for selectively establishing a drive power gear train in the transmission in response to the reciprocating movement of the shift rod.
2. Description of the Prior Art
In such a conventional shift mechanism as described above, it is difficult to repair a control system for the pneumatic or hydraulic actuator upon the occurrence of problems in its operation or when damage to the same has occurred. It is, therefore, necessary to drive the vehicle to a well-equipped service shop or factory for repairing the problems with or the damage to the control system. In such a situation, it has been, however, experienced that the shift rod is unexpectedly displaced from its shifted position to an intermediate position in spite of the provision of a detent mechanism associated therewith. This results in trouble in operation of the transmission.